Method and apparatus for recording and reproducing trick play data to and from a digital video tape

ABSTRACT

A method for recording and reproducing trick play data to and from a digital video tape is provided. In the recording method, an advanced television (ATV) signal which contains normal data used during a normal play mode and intra-frame data used during a trick play mode is input. Furthermore, the intra-frame data, which is capable of being independently decoded, is extracted from the ATV signal. Then, the size of the intra-frame data is adjusted to a predetermined picture size by partially decoding the intra-frame data to produce windowed intra-frame data, and the windowed intra-frame data is recorded as trick play data on the digital video tape. In the reproducing method, the ATV signal containing the normal and trick play data are reproduced from the digital video tape. Moreover, the trick play data is extracted from the ATV signal and formatted during a trick play mode, and the normal data is extracted from the ATV signal during a normal play mode. Then, the normal play data or trick play data is selectively output to a decoder. Accordingly, the method enables various types of video head scanners to record or reproduce the trick play data at a maximum multiple-speed (e.g. a 13-multiple-speed) or less than the maximum multiple-speed. In addition, a recording and reproducing apparatus which performs the method above is also provided.

This is a continuation of application Ser. No. 08/611,847 filed Mar. 8,1996, U.S. Pat. No. 5,832,172.

FIELD OF THE INVENTION

The present invention relates to method and apparatus for recording andreproducing data to and from digital video tapes. More particularly, theinvention relates to a method and apparatus for recording andreproducing an advanced television (ATV) signal having trick play datato and from digital video tapes.

BACKGROUND OF THE INVENTION

A digital standard definition-video cassette recorder (SD-VCR) that iscapable of recording and reproducing ATV signals on digital video tapesis currently being developed for consumer use. Furthermore, the SD-VCRis able to transmit data at 24.9 Mbits per second, and the ATV signalwhich is recorded or reproduced from the SD-VCR has a transmission rateof 19.3 Mbits per second. Consequently, the SD-VCR is capable ofrecording or reproducing additional data to and from the video tape at arate of 5.6 Mbits per second.

In order to more fully utilize the unused area of the video tape,various methods are currently being tested in which trick play data isrecorded in the unused area so that the ATV signal can be reproducedduring a trick play mode (e.g. a high speed forward reproduction mode, ahigh speed reverse reproduction mode, or any other non-normal speedreproduction mode). Furthermore, developing an efficient process forrecording and reproducing such trick play data is essential for enablingvarious types of scanners (i.e. video heads) to reproduce signals at avariety of speeds during the trick play mode. Furthermore, such methodwill also improve the image quality of video signals and remove noisefrom the video signals.

In order to provide a better understanding of the present invention, thecomposition of an ATV signal will be briefly described below inconjunction with FIG. 1. As shown in the figure, the ATV signal containsa transport bit stream which includes a series of groups-of-pictures(GOPs), and each GOP has a certain number of pictures (e.g. 12 pictures)arranged in a particular order. The various pictures contained in theGOP may include intra-coded pictures (I-pictures), predictive-codedpictures (P-pictures), and bidirectionally predictive-coded pictures(B-pictures).

The I-pictures are digitally represented by the greatest number of bitsand have the most significant effect upon the image quality of theentire GOP and the capability of encoding the various P-pictures. Sincethe I-pictures, or intra-frames, contain a large number of bits, theycan be independently coded and decoded.

The P-pictures are represented by fewer bits than the I-pictures and arecoded or decoded based on the information contained in the variousI-pictures. Specifically, the P-pictures are predicted frames which areencoded by compensating for the movement contained in the previousintra-frames or the previous predicted frames.

The B-pictures are represented by a smaller number of bits than theP-pictures and are coded or decoded in accordance with the informationcontained in the various I-pictures and P-pictures. In particular, theB-pictures are bidirectionally predicted frames which are encoded bycompensating for the movement contained in the previous intra-frames,subsequent intra-frames, previous predicted frames, and/or subsequentpredicted frames.

When all of the I-pictures, P-pictures, and B-pictures are encoded, theyare arranged in a predetermined order to form the GOP. For instance, asillustrated in FIG. 1, the pictures are organized in the followingorder: I-B-B-P-B-B-P-B-B-P-B-B-I.

Each of the pictures are further divided into various segments.Specifically, each picture contains a certain number of slices, and eachslice includes a predetermined number of macro blocks. In addition, eachmacro block comprises a number of discrete cosine transform (DCT)blocks.

Conventional apparatuses cannot appropriately record and reproducenormal video data and trick play data when the ATV signal is recorded orreproduced in accordance with a Moving Picture Expert Group (MPEG)-2format. For example, when the ATV signal is recorded, the P-pictures andB-pictures can only be decoded after the I-pictures have been completelydecoded. As a result, decoding the P-pictures and B-pictures andreproducing the ATV signal at a high-speed is impossible.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a method for recordingand reproducing trick play data to and from a digital video tape.Furthermore, the trick play data is recorded by partially decoding bitstreams of intra-coded pictures contained in a group of pictures andrecording the decoded bit streams in certain tracks of the digital videotape. Also, the trick play data is reproduced by reading the decoded bitstreams from the certain tracks of the video tape.

Another object of the present invention is to provide an apparatus forperforming the recording and reproducing methods above.

To achieve one of the objects above, a method for recording trick playdata and normal data on a digital video tape is provided. Specifically,the trick play data is used in a trick play mode and the normal data isused in a normal play mode, the trick play data is contained in anadvanced television signal which includes first frame data and secondframe data, and the method comprises the steps of: (a) decoding theadvanced television signal to obtain side information; (b) storing thenormal data contained in the advanced television signal; (c) selectingthe first frame data from the advanced television signal; (d) adjustinga picture size of the first frame data based on the side information toproduce windowed first frame data having a predetermined picture size;(e) converting the windowed first frame data into an MPEG-2 bit stream;(f) correcting header information contained in the MPEG-2 bit stream inaccordance with the side information; (g) mixing the normal data and theMPEG-2 bit stream to produce mixed data; (h) formatting the mixed datainto formatted data, wherein the formatted data comprises sync blocks;(i) adding various codes to the formatted data; and (j) recording theformatted data on the digital video tape such that the first frame dataand the second frame data are recorded on the digital video tape andrespectively correspond to the trick play data and the normal data.

To achieve another one of the objects above, a method for reproducingtrick play data and normal data from a digital video tape is provided.In particular, the trick play data is used in a trick play mode and thenormal data is used in a normal play mode, the trick play datacorresponds to first frame data contained in an advanced television bitstream previously recorded on the digital video tape, and the methodcomprises the steps of: (a) reproducing the advanced television bitstream from the digital video tape; (b) determining whether the advancedtelevision bit stream is being reproduced during the normal play mode orthe trick play mode; (c) extracting the normal data from the advancedtelevision bit stream when the advanced television bit stream is beingreproduced during the normal play mode; (d) extracting the first framedata from the advanced television bit stream when the advancedtelevision bit stream is being reproduced during the trick play mode;(e) temporarily storing the first frame data after the first frame datahas been extracted; and (f) selectively outputting the first frame dataor the normal data to a decoder.

To achieve a further object of the present invention, an apparatus forrecording trick play data and normal data on a digital video tape isprovided. Specifically, the trick play data is used in a trick play modeand the normal data is used in a normal play mode, the trick play datais contained in an advanced television signal which includes first framedata and second frame data, and the apparatus comprises: frame selectingmeans for decoding the advanced television signal to obtain sideinformation, for storing the normal data contained in the advancedtelevision signal, and for selecting the first frame data from theadvanced television signal; windowing means for adjusting a picture sizeof the first frame data output from the first selecting means based onthe side information to produce windowed first frame data having apredetermined picture size; information correcting means for convertingthe windowed first frame data into an MPEG-2 bit stream and forcorrecting header information contained in the MPEG-2 bit stream inaccordance with the side information; data mixing means for mixing thenormal data and the MPEG-2 bit stream to produce mixed data; formattingmeans for formatting the mixed data into formatted data, wherein theformatted data comprises sync blocks; adding means for adding variouscodes to the formatted data; and recording means for recording theformatted data on the digital video tape such that the first frame dataand the second frame data are recorded on the digital video tape andrespectively correspond to the trick play data and the normal data.

To achieve yet another object of the present invention, an apparatus forreproducing trick play data and normal data from a digital video tape isprovided. The trick play data is used in a trick play mode and thenormal data is used in a normal play mode, the trick play datacorresponds to first frame data contained in an advanced television bitstream previously recorded on the digital video tape, and the apparatuscomprises: reproducing means for reproducing the advanced television bitstream from the digital video tape; system control means for determiningwhether reproducing means is reproducing the advanced television bitstream during the normal play mode or the trick play mode; normal dataextracting means for extracting the normal data from the advancedtelevision bit stream when the advanced television bit stream is beingreproduced during the normal play mode; trick data extracting means forextracting the first frame data from the advanced television bit streamwhen the advanced television bit stream is being reproduced during thetrick play mode; storing means for temporarily storing the first framedata after the first frame data has been extracted by the trick dataextracting means; and selecting means for selectively outputting thefirst frame data output from the storing means or the normal data outputfrom the normal data extracting means to a decoder.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will becomemore apparent by describing in detail a preferred embodiment thereofwith reference to the attached drawings in which:

FIG. 1 illustrates a group of pictures having three types of codedpictures;

FIG. 2 illustrates a track of a digital video tape used in a standarddefinition-video cassette recorder;

FIG. 3A illustrates the video head structure and track scan path of afirst type of scanner capable of reproducing a signal recorded on thetape illustrated in FIG. 2;

FIG. 3B illustrates the video head structure and track scan path of asecond type of scanner capable of reproducing a signal recorded on thetape illustrated in FIG. 2;

FIG. 3C illustrates the video head structure and track scan path of athird type of scanner capable of reproducing a signal recorded on thetape illustrated in FIG. 2;

FIG. 4 illustrates a video sector of each track of the digital videotape shown in FIG. 2;

FIG. 5 shows a flow chart for explaining a method for recording trickplay data on a digital video tape in accordance with the presentinvention;

FIG. 6 shows a flow chart of the detailed operations of a frameselecting portion of a recording apparatus which records trick play dataon a digital video tape;

FIG. 7 shows a flow chart for explaining a method for reproducing trickplay data from a digital video tape in accordance with the presentinvention;

FIG. 8 is a block diagram of a recording apparatus which records trickplay data on a digital video tape in accordance with the presentinvention;

FIG. 9 is a block diagram of a frame selecting portion of the recordingapparatus shown in FIG. 8;

FIG. 10 is a diagram for explaining a method of adjusting a size of anintra-frame contained in an advanced television signal; and

FIG. 11 is a block diagram of a reproducing apparatus which reproducestrick play data from a digital video tape in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order to more fully understand the present invention, a digital videotape and various video heads (or scanners) used in a standarddefinition-video cassette recorder (SD-VCR) will be described. Anexample of a track of the digital video tape is shown in FIG. 2. Inparticular, the track contains an insert and track information (ITI)sector 2, an audio sector 4, a video sector 6, and a subcode sector 8.Furthermore, gaps are located between each of the sectors, and the trackis scanned by a video head in a direction from the ITI sector 2 towardsthe subcode sector 8.

The ITI sector 2 contains a pre-amble area, a start-sync block area, atrack information area, and a post-amble area. In addition, the subcodesector 8 has a subcode pre-amble area, a subcode sync block area, and asubcode post-amble area. Moreover, an overwrite margin is located afterthe subcode sector 8 to provide a buffer between adjacent tracks of thevideo tape.

An example of the video sector 6 shown in FIG. 2 is illustrated in FIG.4. Specifically, the video sector 6 comprises 149 sync blocks which arerespectively numbered as sync block 19 to sync block 167. Furthermore,each of the sync blocks 19 to 167 comprises 90 bytes of data whichcontain a 2-byte sync code 18, a 3-byte identification code 20, a77-byte data area 22, and an 8-byte inner parity region 24.

In addition, the 77-byte data area 22 for the various sync blocks 19 to167 store different types of data. Specifically, the data area 22corresponding to the sync blocks 19 and 20 constitute a first videoauxiliary data region 10, and the data area 22 contained in the syncblocks 21 to 155 represent a normal and trick play data region 12.Furthermore, the data area 22 included within the sync blocks 156 and157 designate a second video auxiliary data region 14, and the data area22 corresponding to the sync blocks 158 to 167 constitute an outerparity region 16.

The SD-VCR records an ATV signal in the recording area of the trackdescribed above. Specifically, the audio and video data which arecontained in the ATV signal and correspond to normal play data arerespectively recorded in the audio and video sectors 4 and 6.Furthermore, the SD-VCR is capable of transmitting data at a rate of24.9 Mbits per second, but the bit stream of the ATV signal istransmitted at a rate of 19.3 Mbits per second. Consequently, after theATV signal for the normal play mode is recorded on the video tape, anarea remains on the video tape in which additional data can be recordedat a rate of 5.6 Mbits per second. Thus, trick play data correspondingto a trick play mode may be recorded in this remaining area.

The various video scanners which may be implemented in an SD-VCR and thescan paths traveled by such scanners are illustrated in FIGS. 3A to 3C.Specifically, the figures respectively show overhead views of a 2-headscanner, a 1-double azimuth head scanner, and a 2-double azimuth headscanner. Since a SD-VCR may contain any of the above scanners, a methodand/or apparatus for recording and reproducing trick play data via anSD-VCR should be able to adapt to each of the scanners.

One embodiment of an apparatus for recording trick play data on adigital video tape is shown in FIG. 8. In particular, the recordingapparatus comprises a frame selecting portion 150, a windowing portion152, an information correcting portion 154, a data mixing portion 156, aformatting and encoding portion 158, and a recording portion 160.Furthermore, an example of the detailed structure of the frame selectingportion 150 is illustrated in FIG. 9. Specifically, the portion 150comprises a first decoder 170, a second decoder 172, a first storageportion 174, a second storage portion 176, and a first frame selector178.

The process by which the recording apparatus records trick play data ona digital video tape will be described below in conjunction with FIGS. 5and 6. As shown in FIG. 5, the frame selecting portion 150 inputs an ATVsignal via an input port IN1 and extracts intra-frame data (i.e. firstframe data) from such signal (step 100). Also, in the current example,the intra-frame can be independently decoded and corresponds to trickplay data.

The selection process performed by the selecting portion 150 in step 100is illustrated in more detail in FIG. 6. In particular, the ATV signalis simultaneously input from the input port IN1 and supplied to thefirst storage portion 174 and the first decoder 170. Then, the firststorage portion 174 stores the normal data contained in the ATV signal(step 112), and the first decoder 170 extracts and decodes a transportlayer header from the ATV signal (step 114). Afterwards, the seconddecoder 172 inputs the video signal output from the first decoder 170and extracts a video layer header from such signal (step 116). Then, thetransport layer header and the video layer header are supplied to thesecond storage portion 176, and the storage portion 176 stores the layerheaders as side information (step 118). Meanwhile, the first frameselector 178 inputs the video signal output from the second decoder 172and selects the intra-frame data from the ATV signal.

After the frame selection portion 150 selects the intra-frame, theintra-frame is output to the windowing portion 152. Then, the windowingportion 152 manipulates the intra-frame so that it fits within a windowhaving a predetermined size (X, Y) (step 102). The process fordetermining the size of such window will be further described below withreference to FIG. 10.

As described above, the trick play data contained within an ATV signalcan be stored in a 5.6 Mbit area of the video tape. Specifically, the5.6 Mbit area (i.e. the surplus area) contains 30 sync blocks of the 135sync blocks constituting the normal and trick play data region 12.Moreover, the 30 sync blocks are stored on 27 tracks (i.e. the surplustracks) of the video tape.

In addition, the video layer header extracted from the second decoder172 comprises a sequence header which contains information thatindicates the horizontal and vertical lengths of the windowcorresponding to the encoded picture. In the MPEG-2 format, the largestpicture contained in the ATV signal bit stream has a picture size of1920×1080. However, since the number of surplus tracks for storing thetrick play data cannot adequately store intra-frames corresponding to ahigh-definition image having a size of 1920×1080, the image is modifiedsuch that it can fit into a window having an appropriate picture size(X, Y).

During the window generating operation shown in FIG. 10, one frame canbe recorded in one track. In addition, a method for extracting trickplay data from an ATV signal by partially decoding an intra-frame havinga certain picture size (e.g. 720×480) is described below.

In the MPEG-2 format, the ATV signal comprises a slice header thatcontains a slice-starting-code. Furthermore, the least significant bitof the slice-starting-code indicates the vertical position of a slice,and thus, the vertical position of the window of an intra-frame can bedetermined. In addition, the ATV signal also contains a macro blockheader that includes a macro block-address-increase code. As a result,the horizontal position can be determined based on such code.

In the present example, the number of DCT blocks used to generate anintra-frame having a picture size of 720×480 is 8100. Furthermore, ifthe MPEG-2 sampling format is a 4:2:0 format, each DCT coefficient isrepresented by 9 bits, and thus, the number of bits needed to representall of the DCT blocks is 72900 (i.e. 8100×9 bits). On the other hand,the number of video bits which can be recorded in one track is 83160bits (i.e. 135 sync blocks×77 bytes×8 bits/byte). Thus, since all of theDCT blocks corresponding to one frame can be represented by 72900 bits,one frame can be completely recorded in one track. Moreover, since thenumber of bits remaining in each track after the DCT blocks have beenrecorded is 10260 (i.e. 83160-72900), 10260 bits of trick play data canalso be recorded in each track.

The DCT coefficients also may be variable-length-encoded, and therefore,the actual number of bits needed to represent each DCT coefficient maybe less than 9 bits. Accordingly, the number of bits available in aparticular track for storing the trick play data may be greater than10260. In addition, as the picture size of the intra-frame becomessmaller, the resolution of the intra-frame increases.

After the size of the intra-frame has been properly adjusted, theinformation correcting portion 154 inputs the intra-frame from thewindowing portion 152 and inputs the side information stored in thesecond storage portion 176 via an input port IN2. Then, the correctingportion 154 transforms the intra-frame data into an MPEG-2 bit streamformat and corrects the header information contained in the intra-framedata based on the side information (step 104).

Afterwards, the data mixing portion 156 inputs the intra-frame data fromthe correcting portion 154 and inputs the normal data stored in firststorage portion 174 via an input port IN3. Then, the mixing portion 156mixes the intra-frame data with the normal data to produce mixed data(step 106).

The mixed data is output to the formatting and encoding portion 158which formats such data. Specifically, the formatting and encodingportion 158 generates sync blocks representing the mixed data andincorporates identification codes within such sync blocks (step 108).Finally, the recording portion 160 inputs the formatted data from theformatting and encoding portion 158 and records the normal data and thetrick play data on the digital video tape (step 110).

An embodiment of an apparatus for reproducing trick play data from adigital video tape is shown in FIG. 11. In particular, the reproducingapparatus comprises a reproducing portion 180, a trick data extractingportion 182, a normal data extracting portion 184, a storing portion186, and a selecting portion 188.

The operation of the reproducing apparatus will be described below withreference to FIG. 7. First, the reproducing portion 180 reproduces theATV signal from the digital video tape (step 130), and a system controlportion (not shown) determines if the ATV signal has been reproducedduring a normal play mode or a trick play mode (step 132).

If the reproduced signal corresponds to a normal play reproduction, theATV signal is output to the normal data extracting portion 184, and theextracting portion 184 extracts the normal data from the ATV signal(step 134). On the other hand, if the reproduced signal relates to atrick play reproduction, the trick data extracting portion 182 inputsthe ATV signal and extracts the trick play data (step 136). Then, thewindowed trick play data is temporarily stored in the storing portion186 and appropriately formatted so that it can be properly decoded (step138). The selecting portion 188 inputs the normal data from the normaldata extracting portion 184 and the trick play data from storing portion186 and selectively outputs either the trick play data or the normaldata to a decoder (step 140).

As described above, the method and apparatus for recording andreproducing trick play data to and from a digital video tape enablesvarious types of scanners to record or reproduce the trick play data ata maximum multiple-speed (e.g. a 13-multiple-speed) or less than themaximum multiple-speed. In addition, a high-speed trick play operationcan be accurately and stably performed during the recording andreproducing of an ATV signal via a VCR. For example, since one GOP has12 frames, the GOP can be recorded in 120 tracks, and 27 tracks of the120 tracks can be used to record trick play data. As a result, ahigh-speed trick play operation can be accurately performed byrepeatedly recording trick play data for one trick play in each of the27 tracks.

Furthermore, the embodiments described above are merely illustrative,and modifications of such embodiments may occur to those skilled in theart. Accordingly, this invention is not to be regarded as limited to theembodiments disclosed herein, but is to be limited only as defined bythe appended claims.

What is claimed is:
 1. A method for reproducing trick play data andnormal data from a digital video tape, wherein said trick play data isused in a trick play mode and said normal data is used in a normal playmode, wherein said trick play data corresponds to first frame datacontained in an advanced television bit stream previously recorded onsaid digital video tape, and wherein the method comprises the stepsof:(a) reproducing said advanced television bit stream from said digitalvideo tape; (b) determining whether said advanced television bit streamis being reproduced during said normal play mode or said trick playmode; (c) extracting said normal data from said advanced television bitstream when said advanced television bit stream is being reproducedduring said normal play mode; and (d) extracting said first frame datafrom said advanced television bit stream when said advanced televisionbit stream is being reproduced during said trick play mode, wherein apicture size of said first frame data is adjusted to a predeterminedpicture size before said first frame data is recorded on said digitalvideo tape, wherein said predetermined picture size is determined basedon side information, and wherein said side information is obtained bydecoding said advanced television bit stream before said advancedtelevision bit stream is recorded on said digital video tape.
 2. Themethod for reproducing according to claim 1, wherein said first framedata is capable of being independently decoded.
 3. A method forreproducing trick play data and normal data from a digital video tape,wherein said trick play data is used in a trick play mode and saidnormal data is used in a normal play mode, wherein said trick play datacorresponds to first frame data contained in an advanced television bitstream previously recorded on said digital video tape, and wherein themethod comprises the steps of:(a) reproducing said advanced televisionbit stream from said digital video tape; (b) determining whether saidadvanced television bit stream is being reproduced during said normalplay mode or said trick play mode; (c) extracting said normal data fromsaid advanced television bit stream when said advanced television bitstream is being reproduced during said normal play mode; and (d)extracting said first frame data from said advanced television bitstream when said advanced television bit stream is being reproducedduring said trick play mode, wherein a picture size of said first framedata is adjusted to a predetermined picture size before said first framedata is recorded on said digital video tape, wherein said predeterminedpicture size is determined based on side information, and wherein saidside information is obtained by decoding said advanced television bitstream before said advanced television bit stream is recorded on saiddigital video tape; (e) temporarily storing said first frame data aftersaid first frame data has been extracted; and (f) selectively outputtingsaid first frame data or said normal data to a decoder.
 4. The methodfor reproducing according to claim 3, wherein said step (e) oftemporarily storing said first frame data comprises the step of:(e1)formatting said first frame data into a format which is compatible withsaid decoder.
 5. An apparatus for reproducing trick play data and normaldata from a digital video tape, wherein said trick play data is used ina trick play mode and said normal data is used in a normal play mode,wherein said trick play data corresponds to first frame data containedin an advanced television bit stream previously recorded on said digitalvideo tape, and wherein the apparatus comprises:reproducing means forreproducing said advanced television bit stream from said digital videotape; system control means for determining whether reproducing means isreproducing said advanced television bit stream during said normal playmode or said trick play mode; normal data extracting means forextracting said normal data from said advanced television bit streamwhen said advanced television bit stream is being reproduced during saidnormal play mode; and trick data extracting means for extracting saidfirst frame data from said advanced television bit stream when saidadvanced television bit stream is being reproduced during said trickplay mode, wherein a picture size of said first frame data is adjustedto a predetermined picture size before said first frame data is recordedon said digital video tape, wherein said predetermined picture size isdetermined based on side information, and wherein said side informationis obtained by decoding said advanced television bit stream before saidadvanced television bit stream is recorded on said digital video tape.6. The apparatus according to claim 5, wherein said first frame data iscapable of being independently decoded.
 7. An apparatus for reproducingtrick play data and normal data from a digital video tape, wherein saidtrick play data is used in a trick play mode and said normal data isused in a normal play mode, wherein said trick play data corresponds tofirst frame data contained in an advanced television bit streampreviously recorded on said digital video tape, and wherein theapparatus comprises:reproducing means for reproducing said advancedtelevision bit stream from said digital video tape; system control meansfor determining whether reproducing means is reproducing said advancedtelevision bit stream during said normal play mode or said trick playmode; normal data extracting means for extracting said normal data fromsaid advanced television bit stream when said advanced television bitstream is being reproduced during said normal play mode; and trick dataextracting means for extracting said first frame data from said advancedtelevision bit stream when said advanced television bit stream is beingreproduced during said trick play mode, wherein a picture size of saidfirst frame data is adjusted to a predetermined picture size before saidfirst frame data is recorded on said digital video tape, wherein saidpredetermined picture size is determined based on side information, andwherein said side information is obtained by decoding said advancedtelevision bit stream before said advanced television bit stream isrecorded on said digital video tape; storing means for temporarilystoring said first frame data after said first frame data has beenextracted by said trick data extracting means; and selecting means forselectively outputting said first frame data output from said storingmeans or said normal data output from said normal data extracting meansto a decoder.
 8. The method for reproducing according to claim 7,wherein said storing means comprises:formatting means for formattingsaid first frame data into a format which is compatible with saiddecoder.